According to a report from Deadline, Tony Shalhoub will be the voice of Splinter. The same report also states that, in the case of Danny Woodburn, he was only guaranteed a physical role which leaves it open for Paramount to bring in voice actors.

Johnny Knoxville was also named to be the voice of Leonardo, while Pete Ploszek portrayed the character for motion-capture.

Woodburn took to his Twitter account to state that his legal team was looking into it.

RE:The very NEW news on #TMNT Voice casting #TonyShaloub I don't have any real info, and my legal team is looking into it. Thnx 4 UR support

"Teenage Mutant Ninja Turtles" has an August 8, 2014 release directed by Jonathan Liebesman, produced by Michael Bay starring Megan Fox as April O'Neil, William Fichtner as Shredder, Pete Ploszek as Leonardo, Alan Ritchson as Raphael, Jeremy Howard as Donatello, Noel Fisher as Michelangelo, Will Arnett as Vernon Fenwick, and Whoopi Goldberg as Bernadette Thompson.

Synopsis:

The city needs heroes. Darkness has settled over New York City as Shredder and his evil Foot Clan have an iron grip on everything from the police to the politicians. The future is grim until four unlikely outcast brothers rise from the sewers and discover their destiny as Teenage Mutant Ninja Turtles. The Turtles must work with fearless reporter April and her wise-cracking cameraman Vern Fenwick to save the city and unravel Shredder’s diabolical plan.